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N Rubinstein

Publications and source records attributed to N Rubinstein.

At least 19 recordsLinked to original sources
PubMed2004

The role of galectins in the initiation, amplification and resolution of the inflammatory response.

Inflammation involves the sequential activation of signalling pathways leading to the production of both pro-inflammatory and anti-inflammatory mediators. Galectins constitute a family of structurally related beta-galactoside-binding proteins, which are defined by their affinity for poly-N-acetyllactosamine-enriched glycoconjugates and sequence similarities in the carbohydrate recognition domain. By crosslinking specific glycoconjugates, different members of the galectin family behave as pro-inflammatory or anti-inflammatory agents, acting at different levels of acute and chronic inflammatory responses. Recent studies highlighted immunomodulatory roles for galectins in vivo in several experimental models of chronic inflammation, suggesting that these carbohydrate-binding proteins may be potential targets for the design of a novel generation of anti-inflammatory agents. In this study, we review recent advances on the role of galectins in the initiation, amplification and resolution of the inflammatory response. In particular, we examine the influence of individual members of this family in regulating cell adhesion, migration, chemotaxis, antigen presentation, immune cell activation and apoptosis. From a better understanding of the molecular basis of galectin-induced immune regulation, we may become able to exploit the potential of these sugar-binding proteins and their glycoligands as suitable therapeutic agents in acute and chronic inflammatory disorders.

Animals↗
PubMed2002

Induction of allogenic T-cell hyporesponsiveness by galectin-1-mediated apoptotic and non-apoptotic mechanisms.

Galectin-1, a beta-galactoside-binding protein expressed at sites of T-cell activation and immune privilege, has shown specific immunosuppressive properties. Because of the implications of this protein in T-cell tolerance and its potential use to avoid graft rejection, we investigated the immunosuppressive effects of galectin-1 in the course of the human allogenic T-cell response. Galectin-1 induced a dose- and carbohydrate-dependent inhibition of the allogenic T-cell response. Addition of galectin-1 to alloreactive lymphocytes resulted in significant apoptosis of CD45R0-positive cells. This negative regulatory effect was accompanied by caspase activation, Bcl-2 downregulation and was prevented by addition of exogenous IL-2. In addition, a significant decrease of IFN-gamma production was detected in the non-apoptotic cell population, following exposure of alloreactive lymphocytes to galectin-1. Moreover, the immunosuppressive activity of this protein did not involve TGF-beta-mediated mechanisms. Since galectin-1 is expressed by activated T cells and could be acting by an autocrine negative loop to control human T-cell reactivity, we finally examined the regulated expression of this protein throughout the allogenic T-cell response. Expression of endogenous galectin-1 was detected at 24 h of cell culture, reaching its maximal levels after 72 h of allostimulation. The present study sets the basis for a potential use of galectin-1 as a selective immunosuppressive agent to limit T-cell-mediated reactivity during the effector phase of the alloimmune response.

Adult↗
PubMed2001

[Galectins: a novel family of proteins involved in the regulation of the immune response. Implications in immunopathological processes].

Galectins have emerged as a new family of closely related carbohydrate-binding proteins, which exert their functions by virtue of their ability to decipher glycocodes on complex glycoconjugates. They have been implicated in different immunological processes, such as lymphocyte adhesion, cytokine production, cell growth regulation, apoptosis and central and peripheral immune tolerance. In the present article we analyze the implications of this protein family in different immune pathologies with up- or down-regulated immune responses, such as autoimmune disorders, acute and chronic inflammation, allergic diseases, infection and metastases. The use of recombinant galectins or their antagonists will have future implications in the diagnosis, prognosis and treatment of these diseases, widening the horizons of molecular immunopathology.

Antigens, Differentiation↗
PubMed2000

Developmental myosin heavy chains in the adult human diaphragm: coexpression patterns and effect of COPD.

In preliminary experiments we noted developmental (i.e., embryonic and neonatal) myosin heavy chains (MHCs) in the diaphragms of patients with severe chronic obstructive pulmonary disease (COPD). We hypothesized that this finding represented new fiber formation secondary to injury associated with the mechanical stress of COPD or previously undescribed MHCs in the human diaphragm. To distinguish between these possibilities, we analyzed diaphragmatic biopsies obtained from 9 patients with severe COPD (forced expiratory volume in 1 s = 21 +/- 2% predicted, residual volume = 283 +/- 22% predicted) and 10 age-matched controls. First, using immunocytochemistry with specific monoclonal antibodies, we noted that control diaphragms had greater proportions of fibers expressing embryonic (50 +/- 2 vs. 28 +/- 3%, P < 0.0001) and neonatal (52 +/- 2 vs. 32 +/- 3%, P < 0.001) MHCs than COPD diaphragms. Second, SDS-PAGE demonstrated that these developmental MHCs represented only a very small fraction of the diaphragmatic MHC content. Third, the RT-PCR demonstrated mRNA coding for embryonic and neonatal MHCs in COPD and control diaphragms. Last, COPD and control diaphragms exhibited normal histology on light microscopy. We conclude that the presence of developmental MHC isoforms does not indicate new fiber formation in diaphragms of patients with severe COPD. Although these results represent the first systematic description of embryonic and neonatal MHCs in normal adult human diaphragms, their function remains to be elucidated.

Adult↗
PubMed1998

Evidence for three adult fast myosin heavy chain isoforms in type II skeletal muscle fibers in pigs.

Three main fiber types (one slow [type I] and two fast [type IIA and IIB] can be distinguished using conventional actomyosin ATPase (AM-ATPase) histochemistry after acidic pretreatment in mature pig skeletal muscle. We report the isolation, characterization, and identification of four adult 3'-untranslated regions corresponding to types I, IIA, IIB, and IIX myosin heavy chains (MyHC) from a cDNA library. Identification of different type II clones was based on sequence homology, in situ hybridizations (ISH), AM-ATPase histochemistry, and immunocytochemistry. Enzyme histochemistry, immunocytochemistry, and ISH were performed on serial transverse sections of longissimus and red portion of semitendinosus muscle. Results showed that all three fast MyHC transcripts were expressed in the longissimus, whereas only type IIA and IIX transcripts were present in deep red semitendinosus muscle. Type I and IIA fibers contained mostly type I and IIA transcripts, respectively, whereas type IIB fibers contained a heterogeneous population of transcripts. In longissimus muscle, 18, 31, and 51% of conventional IIB fibers were pure IIX, hybrid IIX/IIB, and pure IIB fibers, respectively. Conversely, conventional IIB fibers were actually IIX in deep red semitendinosus muscle. Expression of the three fast adult MyHC isoforms in longissimus was spatially regulated around the typical islets of type I fibers encountered in pig skeletal muscle. Thus, IIA fibers were contiguous to type I fibers, pure IIX fibers were in the direct vicinity of type I and IIA fibers, and hybrid IIX/IIB fibers were located mostly within primary fascicles between the islets of type I fibers; however, pure IIB fibers were located mainly at the periphery of the rosettes near the edges of primary fascicles. In light of the present study, conventional IIB fibers, as defined with AM-ATPase staining, are a heterogeneous population that should be split into pure IIX, hybrid IIX/ IIB, and pure IIB fibers for a more accurate fiber typing.

Amino Acid Sequence↗
PubMed1997

Transitory expression of alpha cardiac myosin heavy chain in a subpopulation of secondary generation muscle fibers in the pig.

Unlike the random distribution of fiber types seen in skeletal muscles of most mammals, pig muscle exhibits a rosette pattern consisting of islets of slow fibers surrounded by concentric circles of type IIA and IIB fibers. Within each islet of slow fibers, one of the central fibers is a primary myofiber, whereas all others are secondary fibers. The present study demonstrates that a subpopulation of the slow secondary fibers transiently expresses alpha-myosin heavy chain (MHC). Two cDNA libraries were made from longissimus dorsi skeletal muscle of 14-day-old piglet and adult pig atrium; the latter muscle is mainly composed of alpha-MHC. Screening of the libraries with a human anti-alpha-MHC mAb (F8812F8) demonstrated the presence of positive MHC clones in both libraries; the nucleotide sequence of the 3'-untranslated region (3'-UTR) was identical in both libraries. As this MHC 3'-UTR had 75% homology with the human alpha-MHC, it was identified as pig alpha-MHC. Using specific cRNA probes and mAbs against pig alpha-cardiac and beta/slow/type I MHC, we studied the expression of these MHCs in developing pig semitendinosus muscle by combining in situ hybridization and immunocytochemistry on serial sections at 90 days of gestation, and at 1, 6, 35 days and 6 months of age. The results showed that a subpopulation of secondary fibers that directly abut primary fibers, transiently produced alpha-MHC, both at the levels of the protein and its transcript. Subsequently, these fibres expressed beta-MHC. At 1 day, immunocytochemistry showed that 16% of the secondary fibers expressed alpha-MHC, among which 20% did not yet express beta-MHC. At 6 days, alpha- and beta-MHCs were mostly present in the same fibers, i.e., 23% of the secondary fibers. Thereafter, the proportion of secondary fibers reacting with alpha-MHC mAb decreased to 10% at 5 weeks and 0% at 6 months, whereas beta-MHC was still accumulating in about 38% of the secondary fibers. During the period studied, the distribution of alpha- and beta-MHC transcripts closely matched that of the corresponding proteins. Expression of alpha-MHC was not detected in primary type I muscle fibers and slow type I secondary fibers at the periphery of the rosettes of slow fibers. This study is the first unequivocal demonstration of a transitory expression of alpha-MHC in a subpopulation of secondary fibers in a limb skeletal muscle during mammalian development.

Amino Acid Sequence↗
PubMed1987

Pemphigus foliaceus antibodies and a monoclonal antibody to desmoglein I demonstrate stratified squamous epithelial-specific epitopes of desmosomes.

Pemphigus foliaceus (PF) is a human autoimmune disease in which autoantibodies are directed against the cell surface of epidermal cells. Using an immunoblotting technique, we recently demonstrated that a subgroup of PF patients have autoantibodies to the desmosomal core glycoprotein, desmoglein I (DGI). There are desmosomes in all epithelia and in heart, yet PF affects only stratified squamous epithelia. One explanation for this finding might be that there are tissue-specific differences in desmosomes. Thus, to determine whether certain epitopes of DGI are tissue-restricted, we performed immunofluorescence studies on various monkey tissues with the following antibodies: a rabbit polyclonal antiserum against whole desmosomes, which demonstrated the desmosomes in all tissues tested; a mouse monoclonal antibody against DGI, MmDGI-1; and PF sera that bound DGI on immunoblotting (PF IB+). In addition, we tested the tissues with PF sera that did not bind DGI by immunoblotting (PF IB-) to determine if these sera were different from PF IB+ sera in their tissue specificity. PF IB+, PF IB-, and MmDGI-1 antibodies stained all stratified squamous epithelia tested, including skin, tongue, upper esophagus, conjunctiva, and cornea; however, they did not stain heart or any nonstratified squamous epithelia, including gall bladder, small intestine, liver, ureter, and bladder. These results indicate that there is tissue heterogeneity of desmosomes, and that epitopes on DGI defined by both PF antibodies and a monoclonal antibody are present only in stratified squamous epithelia. In addition, PF IB- sera had the same tissue specificity as PF IB+ sera. These results may partially explain why PF involves only stratified squamous epithelia.

Antibodies, Monoclonal↗
PubMed1986

In vitro and in vivo anti-leishmanial activity of chlorpromazine alone and combined with N-meglumine antimonate.

Chlorpromazine (CPZ) was effective in vitro against leishmanial promastigotes and amastigotes. CPZ at 7.5 micrograms ml-1 killed the promastigotes of Leishmania mexicana, L. aethiopica and L. major within 24 hours of exposure. A higher concentration was required to achieve the same effect against L. donovani. N-meglumine antimonate (MGA) was only partially effective against the promastigotes of the four strains studied. Even at 1000 micrograms ml-1 total destruction of the parasites did not occur within four days of treatment. Combination chemotherapy of CPZ and MGA generally showed an additive effect against promastigotes. However, a synergistic effect was observed in the case of L. donovani promastigotes and L. major amastigotes in vitro. No significant effect was obtained against the amastigotes of L. major and L. mexicana in vivo, in cutaneous lesions of BALB/c mice.

Animals↗
PubMed1985

Influences of testosterone on contractile proteins of the guinea pig temporalis muscle.

The present study outlines the changes in contractile proteins which occur during sexual differentiation of the guinea pig temporalis muscle. This is an androgen sensitive muscle, which in the female progresses from a fetal phenotype to a muscle rich in IIa fibers, and in the male, undergoes a further switch to an almost pure IIb fiber phenotype. We show the IIa to IIb transition in the male involves a change in myosin heavy chain synthesis (Figure 39), a corresponding change in the mobility of native myosin isozymes run on pyrophosphate gels (Figure 43), and changes in the proportions of the alpha and beta subunits of tropomyosin (Figure 41). Myosin light chains appear to be unaltered in this transformation.

Animals↗
PubMed1985

Increased erythrocyte glutathione peroxidase activity in psoriatics consuming high-selenium drinking water at the Dead-Sea Psoriasis Treatment Center.

Erythrocyte selenium-dependent glutathione peroxidase activity was measured in psoriatic Danes, before and after their four-week balneological therapy at the Ein-Bokek International Psoriasis Treatment Center, on the Dead-Sea shore in Israel. The drinking water in Ein-Bokek was found to be rich in selenium, a trace element with anticarcinogenic properties and of great importance in human nutrition and health. The most reliable biological parameter for increase in selenium bioavailability is the erythrocytes' glutathione-peroxidase activity. As psoriasis is a proliferative skin disease, the activity of this enzyme was assayed in 35 psoriatic Danes and in 25 long-term local hotel workers, as well as in 34 volunteers drinking low-selenium water. The glutathione peroxidase activity in the psoriatic patients increased significantly during their four-week stay in Ein-Bokek. Erythrocyte glutathione peroxidase activity in the hotel workers was 50% higher than that in the healthy volunteers consuming low-selenium water. A possible role of selenium in psoriasis is suggested.

Adult↗
PubMed1985

Epidermolysis bullosa acquisita antigen is synthesized by both human keratinocytes and human dermal fibroblasts.

In order to determine the source of epidermolysis bullosa acquisita (EBA) antigen, we studied its synthesis by human keratinocytes and fibroblasts in culture. To identify the antigen, we used the sera of 5 patients with EBA. These sera had antibodies directed against the epidermal basement membrane zone (BMZ) at titers of 5-80. The 5 sera were further characterized by immunoblotting on extracts of the epidermal BMZ. In concert with previous reports, 4 sera stained a 290 kD polypeptide, 3 sera weakly stained a 145 kD polypeptide, and 1 serum did not bind either polypeptide. To study the synthesis of the EBA antigen, cultured human keratinocytes and fibroblasts, derived from neonatal foreskins, were metabolically labeled with 14C-labeled amino acids. Radiolabeled newly synthesized proteins that were extracted from these cultures with nonionic detergent were used in an immunoprecipitation assay. The precipitated proteins were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. All 5 EBA sera, but none of 3 bullous pemphigoid or 4 normal human sera, precipitated a 290 kD polypeptide from extracts of both keratinocytes and fibroblasts. Approximately equal amounts of this 290 kD polypeptide were precipitated from equivalent amounts of extracts from either cell type. The 290 kD polypeptide was also specifically precipitated by EBA sera from extracts of a human squamous cell carcinoma line, SCC-15. The 145 kD polypeptide was not detected in the newly synthesized proteins of any of these cell cultures. This finding suggests that the 145 kD polypeptide is not a precursor of the 290 kD polypeptide. Taken together these results demonstrate that the EBA antigen is synthesized by both human keratinocytes and fibroblasts, and is not a tissue (epidermal)-specific product.

Antigens↗
PubMed1985

Malignant blue nevus.

A malignant blue nevus of the dorsum of the hand and a review of the literature is reported. Histopathologic examination showed the presence of a blue nevus and a cellular blue nevus, as well as a malignant blue nevus. The cellular blue nevus elements of the lesion showed the characteristic prominent neural-type fascicles intertwined with melanocytes. There was no evidence for local invasion or regional lymph node metastases. The patient was free of disease 1 year following wide excision.

Adult↗
PubMed1985

Evidence that beta-endorphin binds to specific receptors in rat peripheral tissues and stimulates the adenylate cyclase-adenosine 3',5'-monophosphate system.

With the use of [125I]acetyl human beta-endorphin (Ac-hBE), specific binding sites for beta-endorphin (BE) were identified in the liver, kidney, adrenal, spleen, and testis of adult male rats, whereas specific BE-binding sites were not present in the ventral prostate or pancreas. In those tissues containing specific BE-binding sites, microsomal membranes (15,000-100,000 X g pellet) exhibited higher BE-binding capacity than the crude homogenate (125-100,000 X g pellet). The binding of BE was saturable, and maximal, specific binding was achieved with a 60-min incubation at 22 C. Furthermore, optimal BE binding was dependent on the presence of magnesium chloride. Scatchard analysis of BE binding to hepatic membranes revealed the existence of two classes of binding sites. One class had an apparent Ka of 0.019 X 10(9) M-1 and a lower number of binding sites (9.1 pmol BE/mg protein), whereas the other class had a lower affinity (apparent Ka of 0.0006 X 10(9) M-1) and a higher number of binding sites (159 pmol/mg protein). Specific BE binding to hepatic membranes was inhibited (80-100%) by rat AcBE-(1-27) and -(1-31), nonacetylated rat BE-(1-31), and human beta-lipotropin. At substantially higher peptide concentrations (greater than 10(-5) M), gamma-endorphin, met-enkephalin, or leu-enkephalin inhibited BE binding by 20-40%. In addition, opiate receptor-binding drugs, such as morphine and naloxone, at 10(-5) M did not alter BE binding to hepatic membranes. Incubation of hepatic membranes with BE induced a dose-related increase in membrane adenylate cyclase activity, and 0.5 X 10(-10) M BE resulted in a maximal enhancement of adenylate cyclase activity to 148% above control values. Water-deprived or salt-loaded male rats with chronically lowered immunoreactive plasma BE exhibited substantially increased BE binding to adrenal and kidney tissue. Specific binding sites for BE occur in a variety of peripheral tissues, and alterations of circulating BE result in changes in the capacity of certain peripheral tissues to bind BE. Finally, occupancy of specific BE-binding sites in peripheral tissue stimulates the adenylate cyclase-cAMP system, which suggests that the peripheral actions of circulating BE may be mediated via this system.

Adenylyl Cyclases↗